The tension between Mamata Banerjee and the Congress boiled over on Wednesday, with the West Bengal Chief Minister accusing the grand old party of taking the help of RSS, the BJP's ideological mentor, on two seats. Mr Gandhi hit back with a reminder. "Has Mamata Banerjee ever compromised with the BJP anywhere?" he said, hinting at her early on-again-off-again relation with the BJP during which she held ministerial berths at the centre.
"Don't give a single vote to the BJP and don't give a vote to the Congress. They are hand-in-glove with the BJP," Ms Banerjee said at a rally.
"In Behrampore, the Congress leader is fighting... I hear with RSS help. In Jangipur, Pranab Mukherjee's son is fighting with RSS help. Even here (in Darjeeling), the RSS is helping the Congress candidate," said the Chief Minister, known these days for her bitter verbal assaults on Prime Minister Narendra Modi, the BJP and the RSS.
"Mamata Banerjee is saying we are not really fighting the BJP. But then, who raised the Rafale issue? Who raised the slogan 'Chowkidar Chor Hai'? We have never compromised with the BJP ever anywhere in any state. Has Mamata Banerjee ever compromised with the BJP anywhere ever?" Mr Gandhi said.
Mamata Banerjee, who started her career in the Congress and formed her own party in 1997, had joined the NDA two years later. She became a minister in the NDA governments led by Atal Bihari Vajpayee, holding the coveted railways and the coal and mines portfolios.
When the Congress came to power in 2004, she developed a rapport with Sonia Gandhi, even though she never got along with her son.
In the run-up to the Lok Sabha elections this time, she emerged as a hopeful for the top job in case of an opposition victory -- an ambition that has progressively soured the relation with Rahul Gandhi.
The two parties have not been able to work out an alliance and their candidates will be up against each other in most seats - a situation that's expected to play into the BJP's hands.
Last month, Ms Banerjee and Mr Gandhi had exchanged barbs.
In at his first rally in Bengal ahead of the elections, Rahul Gandhi had attacked Prime Minister Narendra Modi and the Chief Minister in the same breath, saying her rule is no better than the Left's.
The Chief Minister hit back three days later. "He is just a kid. What will I say about it?" she responded to reporters' queries on the subject.